Add a warning to drop database wait if there are still open handles on a table

  Add some more safety if MySQL tries to drop a table on which there are open handles

  Try to make sure DROP DATABASE does not cause a deadlock because we now let InnoDB wait MySQL does not have open handles to tables we drop

  DROP DATABASE required that the database name is in lower case to work; put it always to lower case in innobase_drop_database

  Changed C++ style comments to ANSI C style.

into donna.mysql.fi:/home/heikki/mysqln

  If the default character set was set to non-latin1 then the collation order of DATA_CHAR and DATA_VARCHAR was not defined, and foreign key system tables did not work, because they contain DATA_VARCHAR columns

  Still a little better error message for Harald Fuchs

  Add some error messages to help in tracking Harald Fuchs' foreign key failure

Fix of InnoDB variables in SHOW VARIABLES
Fix for ALTER TABLE and InnoDB

  Prevent a foreign key constraint references between INT columns where the signedness is different

  Remove use of prebuilt->trx, better play safe since we do not know MySQL call order of external_lock

  Small improvements
row0mysql.c:
  Small improvements + fix the ALTER TABLE problem by introducing a lazy drop table it can use
ha_innobase.cc:
  Some fine-tuning of optimization

  Fix the crashes reported by Peter; SHOW CREATE does not call external_lock before calling ::info, and consequently the trx struct in prebuilt is obsolete; setting trx->op_info caused erratic memory corruption in mysqldump

into donna.mysql.fi:/home/heikki/mysqln

  Fine-tune optimization parameters; in small tables the estimates are accurate; in big tables let us not be too optimistic about index selectivity

  Assume selectivity of any key prefix is better than 1 / 100, regardless of what the estimator returns; this balances the pessimistic assumption of the optimizer thatany secondary key access to the full row incurs a page read from disk